颗粒粒径对流态化还原铁矿粉黏结失流的影响

采用热态可视化流化床装置,在一定表观气速条件下,研究1073 K温度时不同粒级铁矿粉的黏结失流.根据对黏结失流影响程度的不同,可将矿粉颗粒分为三个粒径区间:中性气氛升温过程中失流的小粒径颗粒;还原至较低金属化率发生失流的中间粒径颗粒;还原至高金属化率也不发生失流的大粒径颗粒.分别对他们不同的影响机理进行了分析.研究还发现在正常流化条件下,随着矿粉颗粒粒径的增大,还原失流后床层的膨胀幅度会减小.

Influence of particle size on the sticking of iron ore fines in fluidized beds during reduction

By using a thermal-state visualizable fluidized bed,the sticking of iron ore fines with different particle sizes was investigated under the condition of certain superficial gas velocity at 1073 K. It is found that according to different influences of particle size on the sticking,iron ore fines can be divided into three particle size ranges:small particle size at which sticking occurs in the neutral atmosphere under 1073 K,medium particle size at which defluidization happens when iron ore fines are reduced to low metallization ratio on the fluidized bed,and large particle size at which sticking does not appear on the fluidized bed,even to the end of reduction.The influence mechanism of particle size was analyzed in this paper. Moreover,under the normal fluidization condition,the swelling degree of the fixed bed after defluidization decreases with increasing particle size.